Magnetic alloy powder and method for manufacturing same, as well as coil component made of magnetic alloy powder and circuit board carrying same

Active Publication Date: 2020-09-03
TAIYO YUDEN KK
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Benefits of technology

The present invention provides a solution for creating a magnetic alloy powder with high Fe content that also has excellent insulating properties. By heat-treating the powder in the presence of oxygen, a film of Si-rich oxide is formed on the surface of each grain in the powder, which prevents the formation of a thick insulating film and allows for compacting of the metal grains without increasing the distance between them. This results in improved magnetic properties and reduced coating treatment cost. A method for manufacturing the magnetic alloy powder is also provided.

Problems solved by technology

This gives rise to the problem that a relatively lower Fe content in the metal prevents sufficient magnetic properties from being achieved.
As described in Patent Literature 2, on the other hand, adopting a metal magnetic powder of high Fe content such as that of pure iron makes it difficult to form an insulating film due to oxidization of a component in the metal, which necessitates the formation of an insulating film separately by coating the metal grain surface, etc.
The insulating film thus formed is thick, and this gives rise to the problem that, upon compacting, the thickly formed insulating film increases the distance between metal grains due to the thickness of the insulating film, resulting in lower magnetic properties.
Other problems include, for example, peeling, loss, etc., of the insulating film due to low adhesive strength between the metal grain and the insulating film, as well as higher coating treatment cost.
Also, as described in Patent Literature 3, forming an insulating film by oxidizing Si, which is a non-Fe component contained by a small quantity in the metal, in a weak oxidizing atmosphere can result in lower insulating property because of a thin, brittle SiO2 oxide film peeling or cracking due to handling and thus causing the metal part to be exposed.
Additionally, the metal part, when exposed to air, becomes prone to reacting with oxygen and being oxidized, which is another cause of lower magnetic properties.
This limits the press tonnage when forming a compact, which in turn makes it difficult to achieve both desired insulating property and filling rate.

Method used

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  • Magnetic alloy powder and method for manufacturing same, as well as coil component made of magnetic alloy powder and circuit board carrying same
  • Magnetic alloy powder and method for manufacturing same, as well as coil component made of magnetic alloy powder and circuit board carrying same
  • Magnetic alloy powder and method for manufacturing same, as well as coil component made of magnetic alloy powder and circuit board carrying same

Examples

Experimental program
Comparison scheme
Effect test

example 1

[0089]A material powder for magnetic alloy, having a composition of 96 percent by mass of Fe, 2 percent by mass of Si, 1 percent by mass of Cr, and 1 percent by mass of Al, and an average grain size of 4.0 μm, was put in a container made of zirconia and placed in a vacuum heat treatment furnace.

[0090]Next, the interior of the furnace was evacuated to an oxygen concentration of 5 ppm, after which the temperature was raised to 650° C. at a rate of temperature rise of 5° C. / min and held at that temperature for 5 hours to perform heat treatment, and then the furnace was cooled to room temperature, to obtain the magnetic alloy powder pertaining to Example 1.

[0091]When the obtained magnetic alloy powder was measured, according to the aforementioned method, for the percentage by mass of each element in the alloy phase of the magnetic grain constituting the powder, Fe accounted for 98.0 percent by mass, Si accounted for 1.0 percent by mass, Cr accounted for 0.8 percent by mass, and Al accou...

example 2

[0094]The magnetic alloy powder pertaining to Example 2 was obtained in the same manner as in Example 1, except that the oxygen concentration in the heat treatment atmosphere was changed to 100 ppm.

[0095]When the obtained magnetic alloy powder was measured, according to the same method in Example 1, for the percentage by mass of each element in the alloy phase of the magnetic grain constituting the powder, Fe accounted for 98.1 percent by mass, Si accounted for 0.8 percent by mass, Cr accounted for 0.7 percent by mass, and Al accounted for 0.4 percent by mass.

[0096]Also, when the obtained magnetic alloy powder was measured, according to the same method in Example 1, for the percentage by mass of each element in the oxide film of the magnetic grain constituting the powder, it was confirmed that, at the measurement position where the content of Si was the highest, Si was the element contained in the largest quantity and that Cr and Al were also contained at the above measurement posit...

example 3

[0098]The magnetic alloy powder pertaining to Example 3 was obtained in the same manner as in Example 1, except that the holding time during heat treatment was changed to 10 hours.

[0099]When the obtained magnetic alloy powder was measured, according to the same method in Example 1, for the percentage by mass of each element in the alloy phase of the magnetic grain constituting the powder, Fe accounted for 98.3 percent by mass, Si accounted for 1.7 percent by mass, Cr accounted for 0.6 percent by mass, and Al accounted for 0.4 percent by mass.

[0100]Also, when the obtained magnetic alloy powder was measured, according to the same method in Example 1, for the percentage by mass of each element in the oxide film of the magnetic grain constituting the powder, it was confirmed that, at the measurement position where the content of Si was the highest, Si was the element contained in the largest quantity and that Cr and Al were also contained at this measurement position.

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Abstract

In an exemplary embodiment, a magnetic alloy powder is constituted by magnetic grains 100 whose alloy phase 1 is coated with an oxide film 2, wherein: the alloy phase 1 has a Fe content of 98 percent by mass or higher and also contains Si and at least one type of non-Si element that oxidizes more easily than Fe (element M); and the oxide film 2 is such that, at the location where the content of Si as expressed in percentage by mass is the highest according to the element distributions in the direction of film thickness, this content of Si is higher than the content of Fe, and also higher than the content of element M, at this location. The magnetic alloy powder has a high Fe content and also offers excellent insulating property.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS[0001]The present application claims priority to Japanese Patent Application No. 2019-036939, filed Feb. 28, 2019 and 2019-227863, filed Dec. 18, 2019, the disclosures of which are incorporated herein by reference in their entirety including any and all particular combinations of the features disclosed therein.BACKGROUNDField of the Invention[0002]The present invention relates to a magnetic alloy powder and a method for manufacturing the same, as well as a coil component made of the magnetic alloy powder and a circuit board carrying the same.Description of the Related Art[0003]Emergence of higher-performance electrical and electronic devices is driving the need, in recent years, for inductors and other coil components offering improved performance in smaller sizes. Since the performance of a coil component is affected by the quantity of the magnetic material contained therein, enhancing the performance of the magnetic material is necessary to r...

Claims

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Application Information

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IPC IPC(8): C22C38/02C22C33/02C22C38/18C22C38/14C22C38/06C22C33/04B22F1/142B22F1/145B22F1/16
CPCC22C38/02C22C2202/02C22C38/14C22C33/0264C22C33/04C22C38/06C22C38/18H01F1/33H01F1/14766H01F41/0253H01F27/28H05K1/18C22C38/34B22F1/142B22F1/145B22F1/16C22C33/0228
Inventor ORIMO, YOKOKASHIWA, TOMOO
Owner TAIYO YUDEN KK
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